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124 lines
4.2 KiB
124 lines
4.2 KiB
// pkcspad.cpp - written and placed in the public domain by Wei Dai
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#include "pch.h"
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#ifndef CRYPTOPP_PKCSPAD_CPP // SunCC workaround: compiler could cause this file to be included twice
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#define CRYPTOPP_PKCSPAD_CPP
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#include "pkcspad.h"
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#include <assert.h>
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NAMESPACE_BEGIN(CryptoPP)
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// more in dll.cpp
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template<> const byte PKCS_DigestDecoration<Weak1::MD2>::decoration[] = {0x30,0x20,0x30,0x0c,0x06,0x08,0x2a,0x86,0x48,0x86,0xf7,0x0d,0x02,0x02,0x05,0x00,0x04,0x10};
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template<> const unsigned int PKCS_DigestDecoration<Weak1::MD2>::length = sizeof(PKCS_DigestDecoration<Weak1::MD2>::decoration);
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template<> const byte PKCS_DigestDecoration<Weak1::MD5>::decoration[] = {0x30,0x20,0x30,0x0c,0x06,0x08,0x2a,0x86,0x48,0x86,0xf7,0x0d,0x02,0x05,0x05,0x00,0x04,0x10};
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template<> const unsigned int PKCS_DigestDecoration<Weak1::MD5>::length = sizeof(PKCS_DigestDecoration<Weak1::MD5>::decoration);
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template<> const byte PKCS_DigestDecoration<RIPEMD160>::decoration[] = {0x30,0x21,0x30,0x09,0x06,0x05,0x2b,0x24,0x03,0x02,0x01,0x05,0x00,0x04,0x14};
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template<> const unsigned int PKCS_DigestDecoration<RIPEMD160>::length = sizeof(PKCS_DigestDecoration<RIPEMD160>::decoration);
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template<> const byte PKCS_DigestDecoration<Tiger>::decoration[] = {0x30,0x29,0x30,0x0D,0x06,0x09,0x2B,0x06,0x01,0x04,0x01,0xDA,0x47,0x0C,0x02,0x05,0x00,0x04,0x18};
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template<> const unsigned int PKCS_DigestDecoration<Tiger>::length = sizeof(PKCS_DigestDecoration<Tiger>::decoration);
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size_t PKCS_EncryptionPaddingScheme::MaxUnpaddedLength(size_t paddedLength) const
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{
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return SaturatingSubtract(paddedLength/8, 10U);
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}
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void PKCS_EncryptionPaddingScheme::Pad(RandomNumberGenerator &rng, const byte *input, size_t inputLen, byte *pkcsBlock, size_t pkcsBlockLen, const NameValuePairs ¶meters) const
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{
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assert (inputLen <= MaxUnpaddedLength(pkcsBlockLen)); // this should be checked by caller
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// convert from bit length to byte length
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if (pkcsBlockLen % 8 != 0)
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{
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pkcsBlock[0] = 0;
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pkcsBlock++;
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}
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pkcsBlockLen /= 8;
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pkcsBlock[0] = 2; // block type 2
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// pad with non-zero random bytes
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for (unsigned i = 1; i < pkcsBlockLen-inputLen-1; i++)
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pkcsBlock[i] = (byte)rng.GenerateWord32(1, 0xff);
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pkcsBlock[pkcsBlockLen-inputLen-1] = 0; // separator
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memcpy(pkcsBlock+pkcsBlockLen-inputLen, input, inputLen);
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}
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DecodingResult PKCS_EncryptionPaddingScheme::Unpad(const byte *pkcsBlock, size_t pkcsBlockLen, byte *output, const NameValuePairs ¶meters) const
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{
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bool invalid = false;
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size_t maxOutputLen = MaxUnpaddedLength(pkcsBlockLen);
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// convert from bit length to byte length
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if (pkcsBlockLen % 8 != 0)
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{
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invalid = (pkcsBlock[0] != 0) || invalid;
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pkcsBlock++;
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}
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pkcsBlockLen /= 8;
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// Require block type 2.
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invalid = (pkcsBlock[0] != 2) || invalid;
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// skip past the padding until we find the separator
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size_t i=1;
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while (i<pkcsBlockLen && pkcsBlock[i++]) { // null body
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}
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assert(i==pkcsBlockLen || pkcsBlock[i-1]==0);
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size_t outputLen = pkcsBlockLen - i;
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invalid = (outputLen > maxOutputLen) || invalid;
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if (invalid)
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return DecodingResult();
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memcpy (output, pkcsBlock+i, outputLen);
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return DecodingResult(outputLen);
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}
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// ********************************************************
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#ifndef CRYPTOPP_IMPORTS
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void PKCS1v15_SignatureMessageEncodingMethod::ComputeMessageRepresentative(RandomNumberGenerator &rng,
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const byte *recoverableMessage, size_t recoverableMessageLength,
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HashTransformation &hash, HashIdentifier hashIdentifier, bool messageEmpty,
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byte *representative, size_t representativeBitLength) const
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{
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assert(representativeBitLength >= MinRepresentativeBitLength(hashIdentifier.second, hash.DigestSize()));
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size_t pkcsBlockLen = representativeBitLength;
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// convert from bit length to byte length
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if (pkcsBlockLen % 8 != 0)
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{
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representative[0] = 0;
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representative++;
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}
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pkcsBlockLen /= 8;
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representative[0] = 1; // block type 1
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unsigned int digestSize = hash.DigestSize();
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byte *pPadding = representative + 1;
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byte *pDigest = representative + pkcsBlockLen - digestSize;
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byte *pHashId = pDigest - hashIdentifier.second;
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byte *pSeparator = pHashId - 1;
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// pad with 0xff
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memset(pPadding, 0xff, pSeparator-pPadding);
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*pSeparator = 0;
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memcpy(pHashId, hashIdentifier.first, hashIdentifier.second);
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hash.Final(pDigest);
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}
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#endif
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NAMESPACE_END
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#endif
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